2012 Mazda CX - 9 Touring (3.7 Liter - V6) (106,000 miles) is blowing an OBD Code: P2272 and P2A04. I wanted to verify (1) that this is the oxygen sensor #2 and (2) the sensor is lower of the 2 oxygen sensors of the right lower side of the engine. Looks like the replacement is around $66 at Advanced Auto. Many Thanks!

 

Having same issue.
replaced with a generic Amazon O2 and it came back.
Replaced with a Bosch and still came back.
doesn’t affect drivability, mileage, performance.
only comes on when starting. If I reset it while driving it stays off till restart.

what could it be ?

 

Thats because it was not the sensor.

I keep recommending on this forum as well about 11 other various platform

DONT REPACE PARTS BEFOR YOUR TEST AND CONFIRM THAT THEY ARE BAD!

Diagnostic codes are more or less as a starting point only to test that area and the parts related to it. Many times, randomly changing a part thought to be bad can complicate and even in some case create more additional problems not related to the original problem!

 

Then what else can it be ?
I am not getting any voltage readings feom the sensor.
The next thing is wiring but I need a schematic.

 

You need to access by using a good quality Diagnostic scanner and connect to the diagnostic connector and read the HO2 values. While there look for current DTC and also pending and permanent DTCs. If you have access look at the monitors for their state of readiness? Then you can look at wiring connectors and even the possibility that your ECU is corrupt These are at least a start. Looking at a wire schematic until you have a better idea what caused the issue is only going to frustrate you.

 

This is what I get with my scanner.

 

This phone aps often don't work very well. Please get or have done and connect directly to the OBDII diagnostic connecter with a quality Diagnostic scanner.
Sorry but those reading look more like a transfer of information blue tooth issue then actual information form the ECU

I need a mic to post write for me because of length of explanation information on all the problems with that reported screen shot and possible problems and inaccurate reporting information.

Sorry.
You could have a failing CAT, failing ECU, failing fuel pump, failing IAT,MAP or other sensors....etc etc etc..

 

I did borrow a friends plug in hand held unit and got 5he same readings.
with 2 sensors not reading it leads me to wiring.
car runs great despite the code, weird

 

It may seem the engine is running normal.....but....

if the HO2 are not reporting the correct range and the sampling between the 2 may be incorrect. I don't see that on the any of your postings? you could be running lean? You can check the CAT/ F If this is the case to continue to run without solving the problem could do engine damage or CAT damage.
Not sure why you keep thinking its in the wiring, unless you see some physical damage or any area that may have gotten soaked and saturated with water?

As we already know the DTC I would suggest CLEAR all the value and reset the monitors. Then drive until you get the engine check light and immediately check what DTC they are. Note them. Then before you start the next day recheck and see what information the ECU has in all the area's for DTC files . Start the engine and drive about 10-15 miles or 1/2 hour and recheck the ECU and note any and all DTC. Also go to the readiness file and see what is not changed or if they are all green or if any are in fault! This will indicate what emission systems are effected by your engine DTC and issues.